Random propylene copolymer for bottles with good optical properties and low hexane content

ABSTRACT

Propylene copolymer having a melt flow rate MFR 2  (230° C.) in the range of more than 0.8 to below 2.5 g/10 min, a xylene cold soluble content (XCS) in the range of 25.0 to 35.0 wt.-%, a comonomer content in the range of more than 4.5 to 10.0 wt.-%, wherein further the xylene cold soluble (XCS) fraction of the propylene copolymer has comonomer content in the range of 12.0 to 22.0 wt.-% and the xylene cold insoluble (XCI) fraction of the propylene copolymer has a Mw/Mn of more than 4.9 to 10.0.

The present invention is directed to a new soft propylene copolymer aswell as to extrusion blow molded articles comprising the new softpropylene copolymer.

Polymers are increasingly used in different demanding applications. Atthe same time there is a continuous seek for tailored polymers whichmeet the requirements of these applications. The demands can bechallenging, since many polymer properties are directly or indirectlyinterrelated. For instance, heterophasic systems are known for theirgood impact behavior. Such heterophasic propylene copolymers comprise amatrix being either a propylene homopolymer or a random propylenecopolymer in which an elastomeric copolymer is dispersed. Thus thepolypropylene matrix contains (finely) dispersed inclusions being notpart of the matrix and said inclusions contain the elastomericcopolymer. The term “inclusion” according indicates that the matrix andthe inclusion form different phases within the heterophasic system, saidinclusions are for instance visible by high resolution microscopy, likeelectron microscopy or atomic force microscopy, or by dynamic mechanicalthermal analysis (DMTA). Specifically in DMTA the presence of amultiphase structure can be identified by the presence of at least twodistinct glass transition temperatures.

Soft heterophasic systems which enable a skilled artisan to producetransparent and sterilisable extrusion blow moulded articles are still achallenge.

A specific soft heterophasic propylene copolymer is described in WO2008/141934 A1. This heterophasic propylene copolymer has a rather lowmelting temperature and low stiffness.

However in the field of extrusion blow molded articles good opticalproperties are required. It had become clear in the meantime that hazeshould not be the only value to be used for judging the quality of theoptical properties of extrusion blow molded articles. For instance ithas been recognized that the visual appearance of extrusion moldedarticles is inacceptable even though the haze values have been ratherlow. Thus it became clear that the haze values alone were not enough tojudge the optical appearance of the bottles and hence a new parameter,the so-called bottle appearance factor (BAF), was defined asBAF=(clarity*gloss)/haze.

Beside the optical properties the hexane soluble content of softheterophasic propylene copolymers is a critical issue. However a lowhexane content is an indispensable requirement in the food and healthsector.

Accordingly it is the object of the present invention to provide apropylene copolymer with good optical properties, i.e. with a high BAFvalue, paired with an acceptable hexane content.

The finding of the present invention is to provide a propylene copolymerwith rather high overall comonomer content but moderate xylene coldsoluble (XCS) content. Further the propylene content in the xylene coldsoluble (XCS) fraction should be rather high. A further finding is thatespecially good results are obtained if the matrix of the propylenecopolymer is feature by a bimodal commoner content and molecular weightdistribution.

Accordingly, in a first aspect the present invention is directed to apropylene copolymer having

(a) a melt flow rate MFR₂ (230° C.) measured according to ISO 1133 inthe range of more than 0.8 to below 2.5 g/10 min,(b) a xylene cold soluble content (XCS) determined according ISO 16152(25° C.) in the range of 25.0 to 35.0 wt.-%, and(c) a comonomer content in the range of more than 4.5 to 10.0 wt.-%,wherein further(d) the comonomer content of xylene cold soluble (XCS) fraction of thepropylene copolymer is in the range of 12.0 to 22.0 wt.-%, and(e) the intrinsic viscosity (IV) determined according to DIN ISO 1628/1(in decalin at 135° C.) of the xylene cold soluble (XCS) fraction of thepropylene copolymer is in the range of more than 1.5 to below 3.0 dl/g

Preferably the xylene cold insoluble (XCI) fraction of the propylenecopolymer according to the first aspect has a polydispersity (Mw/Mn) ofmore than 4.9 to 10.0.

In a second aspect the present invention is directed to a propylenecopolymer having

(a) a melt flow rate MFR₂ (230° C.) measured according to ISO 1133 inthe range of more than 0.8 to below 2.5 g/10 min,(b) a xylene cold soluble content (XCS) determined according ISO 16152(25° C.) in the range of 25.0 to 35.0 wt.-%, and(c) a comonomer content in the range of more than 4.5 to 10.0 wt.-%,wherein further(d) the comonomer content of xylene cold soluble (XCS) fraction of thepropylene copolymer is in the range of 12.0 to 22.0 wt.-%, and(e) the xylene cold insoluble (XCI) fraction of the propylene copolymerhas a polydispersity (Mw/Mn) of more than 4.9 to 10.0.

Preferably the xylene cold soluble (XCS) fraction of the propylenecopolymer according to the second aspect has an intrinsic viscosity (IV)determined according to DIN ISO 1628/1 (in decalin at 135° C.) is in therange of more than 1.5 to below 3.0 dl/g.

Preferably, the propylene copolymer according to the first and secondembodiment is α-nucleated, i.e. comprises an α-nucleating agent.

It has surprisingly been found that such propylene copolymer has veryhigh BAF values and relatively low hexane solubles.

In the following the first aspect and second aspect of the presentinvention are defined in more detail together.

The propylene copolymer comprises apart from propylene also comonomers.Preferably the propylene copolymer comprises apart from propyleneethylene and/or C₄ to C₁₂ α-olefins.

Accordingly the term “propylene copolymer” according to this inventionis understood as a polypropylene comprising, preferably consisting of,units derivable from

(a) propyleneand(b) ethylene and/or C₄ to C₁₂ α-olefins.

Thus the propylene copolymer according to this invention comprisesmonomers copolymerizable with propylene, for example comonomers such asethylene and/or C₄ to C₁₂ α-olefins, in particular ethylene and/or C₄ toC₈ α-olefins, e.g. 1-butene and/or 1-hexene. Preferably the propylenecopolymer according to this invention comprises, especially consists of,monomers copolymerizable with propylene from the group consisting ofethylene, 1-butene and 1-hexene. More specifically the propylenecopolymer of this invention comprises—apart from propylene—unitsderivable from ethylene and/or 1-butene. In a preferred embodiment thepropylene copolymer according to this invention comprises unitsderivable from ethylene and propylene only.

Additionally it is appreciated that the propylene copolymer preferablyhas a comonomer content in a very specific range which contributes tothe softness and good optical properties. Thus it is required that thecomonomer content of the propylene copolymer is in the range of 4.5 to10.0 wt.-%, like in the range of 4.5 to below 10.0 wt.-%, morepreferably in the range of 4.5 to 9.5 wt.-%, yet more preferably in therange of equal or more than 5.0 to 9.0 wt.-%, like in the range of equalor more than 6.0 to 9.0 wt.-%.

The propylene copolymer of the instant invention can be further definedby the amount of comonomers within the xylene cold soluble (XCS)fraction. Accordingly it is preferred that the comonomer content in thexylene cold soluble fraction (XCS) of the propylene copolymer is ratherlow. Thus it is appreciated that the comonomer content of the xylenecold soluble fraction (XCS) of the propylene copolymer is in the rangeof 12.0 to 22.0 wt.-%, yet more preferably in the range of 14.0 to 20.0wt.-%, still more preferably in the range of 15.0 to 19.0 wt.-%.

Concerning the comonomers present in the xylene cold soluble fraction(XCS) it is referred to the information provided for the propylenecopolymer. Accordingly in a specific embodiment the xylene cold solublefraction (XCS) comprises, especially consists of, monomerscopolymerizable with propylene from the group consisting of ethylene,1-butene and 1-hexene. More specifically the xylene cold solublefraction (XCS) comprises—apart from propylene—units derivable fromethylene and/or 1-butene. In a preferred embodiment the xylene coldsoluble fraction (XCS) comprises units derivable from ethylene andpropylene only.

Considering the information provided above, it is preferred that thepropylene copolymer fulfills inequation (I), more preferably inequation(Ia), yet more preferably inequation (Ib), still more preferablyinequation (Ic),

$\begin{matrix}{{\frac{{Co}({total})}{{Co}\left( {X\; C\; S} \right)} \leq 0.55},} & {(I),} \\{{\frac{{Co}({total})}{{Co}\left( {X\; C\; S} \right)} \leq 0.50},} & ({Ia}) \\{{0.20 \leq \frac{{Co}({total})}{{Co}\left( {X\; C\; S} \right)} \leq 0.55},} & ({Ib}) \\{{0.30 \leq \frac{{Co}({total})}{{Co}\left( {X\; C\; S} \right)} \leq 0.50},} & \square\end{matrix}$

wherein

-   Co (total) is the comonomer content [wt.-%] of the propylene    copolymer-   Co (XCS) is the comonomer content [wt.-%] of the xylene cold soluble    fraction (XCS) of the propylene copolymer.

Further it is appreciated that the xylene cold soluble (XCS) fraction ofthe propylene copolymer is specified by its intrinsic viscosity. A lowintrinsic viscosity (IV) value reflects a low weight average molecularweight. For the present invention it is preferably required that thexylene cold soluble fraction (XCS) of propylene copolymer has anintrinsic viscosity (IV) measured according to ISO 1628/1 (at 135° C. indecalin) in the range of 1.5 to 3.0 dl/g, like in the range of 1.7 tobelow 2.8 dl/g, more preferably in the range of 1.8 to 2.7 dl/g.

Another characteristic feature of the instant propylene copolymer is itsrather moderate xylene cold soluble (XCS) fraction. Accordingly it isappreciated that the propylene copolymer has a xylene cold solublefraction in the range of 25.0 to 35.0 wt.-%, like in the range of 25.0to below 35.0 wt.-%, more preferably in the range of 27.0 to 34.0 wt.-%,yet more preferably in the range of equal or more than 28.0 to 33.5wt-%.

The part of the propylene copolymer which is not soluble in cold xyleneis the xylene cold insoluble (XCI) fraction. Preferably also thisfraction preferably exhibits some specific properties.

Accordingly it is preferred that the polydispersity (Mw/Mn) of the coldinsoluble fraction (XCI) of the propylene copolymer is in the range ofmore than 4.9 to 10.0, more preferably in the range of 5.0 to 9.0, stillmore preferably in the range of 5.0 to 8.0.

In one preferred embodiment the comonomer content, preferably ethylenecontent, in the cold insoluble fraction (XCI) of the propylene copolymeris in the range of 3.0 to 7.0 wt.-%, yet more preferably in the range of3.5 to 6.0 wt.-%.

Further it is preferred that the comonomer content, preferably ethylenecontent, in both fractions is in a specific ratio to each other.Accordingly it is preferred that the propylene copolymer fulfillsinequation (II) more preferably inequation (IIa), yet more preferablyinequation (IIb),

$\begin{matrix}{2.8 \leq \frac{{Co}\left( {X\; C\; S} \right)}{{Co}\left( {X\; C\; I} \right)} \leq 5.5} & ({II}) \\{3.0 \leq \frac{{Co}\left( {X\; C\; S} \right)}{{Co}\left( {X\; C\; I} \right)} \leq 5.0} & ({IIa}) \\{3.2 \leq \frac{{Co}\left( {X\; C\; S} \right)}{{Co}\left( {X\; C\; I} \right)} \leq 4.8} & ({IIb})\end{matrix}$

wherein

-   Co (XCS) is the comonomer content [wt.-%] of the xylene cold soluble    (XCS) of the propylene copolymer,    Co (XCI) is the comonomer content [wt.-%] of the xylene cold    insoluble (XCI) of the propylene copolymer.

Preferably it is desired that the propylene copolymer is thermomechanically stable, so that for instance a thermal sterilizationprocess can be accomplished. Accordingly it is appreciated that thepropylene copolymer has a melting temperature of at least 145° C., morepreferably in the range of 148 to 159° C., still more preferably in therange of 149 to 157° C., like in the range of 149 to 155° C.

The propylene copolymer according to this invention is further featuredby a rather low melt flow rate MFR₂ (230° C.). Accordingly the propylenecopolymer has a melt flow rate MFR₂ (230° C.) measured according to ISO1133 in the range of more than 0.8 to 2.5 g/10 min, more preferably inthe range of more than 1.0 to 2.2 g/10 min, still more preferably in therange of 1.2 to 2.0 g/10 min.

The instant propylene copolymer is especially further featured by itsspecific optical properties. Accordingly the propylene copolymer has abottle appearance factor (BAF) of formula (I), (Ia), (Ib)

$\begin{matrix}{{B\; A\; F} = {\frac{C \times G}{H} > 8}} & (I) \\{{B\; A\; F} = {\frac{C \times G}{H} > 10}} & ({Ia}) \\{{B\; A\; F} = {\frac{C \times G}{H} > 15}} & ({Ib})\end{matrix}$

whereinH is the haze valueC is the clarity value,G is the gloss value,wherein furtherthe haze, the clarity and the gloss are determined according to ASTM D1003-07 on a test specimen of 0.3×60×60 mm³ size cut from a bottlehaving a wall thickness of 0.3 mm made from the propylene copolymer ofthe instant invention.

Further it is preferred that the propylene copolymer has an hexanesoluble content of below 5.5 wt.-%, more preferably in the range of 0.5to below 5.5 wt.-%, still more preferably in the range of 2.0 to 5.2wt.-%, like in the range of 2.0 to 5.0 wt.-%.

As indicated above, the instant propylene copolymer is featured by aconsiderable amount of a xylene cold soluble (XCS) fraction. On theother hand the propylene copolymer is also preferably featured by arather high amount of a crystalline fraction melting at hightemperature. Accordingly the instant propylene copolymer is a mixture ofa crystalline polymer and amorphous material. Such type of polymer isclassified as heterophasic propylene copolymer. A heterophasic propylenecopolymer comprises a polymer matrix, like a (semi)crystallinepolypropylene, in which the amorphous material, like an elastomericpropylene copolymer, is dispersed. Thus in a preferred embodiment theinstant propylene copolymer is heterophasic propylene copolymer(RAHECO). More precisely the instant propylene copolymer is heterophasicpropylene copolymer (RAHECO) comprising a matrix (M) being a randompropylene copolymer (R-PP) and dispersed therein an elastomericpropylene copolymer (E). Thus the matrix (M) contains (finely) dispersedinclusions being not part of the matrix (M) and said inclusions containthe elastomeric propylene copolymer (E). The term “inclusion” accordingto this invention shall preferably indicate that the matrix and theinclusion form different phases within the heterophasic propylenecopolymer (RAHECO), said inclusions are for instance visible by highresolution microscopy, like electron microscopy or atomic forcemicroscopy, or by dynamic mechanical thermal analysis (DMTA).Specifically in DMTA the presence of a multiphase structure can beidentified by the presence of at least two distinct glass transitiontemperatures.

Preferably the heterophasic propylene copolymer (RAHECO) according tothis invention comprises as polymer components only the random propylenecopolymer (R-PP) and the elastomeric propylene copolymer (E). In otherwords the heterophasic propylene copolymer (RAHECO) may contain furtheradditives, especially α-nucleating agents, but no other polymer in anamount exceeding 5 wt-%, more preferably exceeding 3 wt.-%, likeexceeding 1 wt.-%, based on the total heterophasic propylene copolymer(RAHECO). One additional polymer which may be present in such lowamounts is a polyethylene which is a by-reaction product obtained by thepreparation of heterophasic propylene copolymer (RAHECO) (see in detailbelow). Accordingly it is in particular appreciated that the instantheterophasic propylene copolymer (RAHECO) contains only the randompropylene copolymer (R-PP), the elastomeric propylene copolymer (E) andoptionally polyethylene in amounts as mentioned in this paragraph.

Preferably the weight ratio between the matrix (M), i.e. the randompropylene copolymer (R-PP), and the elastomeric propylene copolymer (E)is 60/40 to 90/10, more preferably 70/30 to 85/15, yet more preferably75/25 to 85/15.

In the following the random propylene copolymer (R-PP) and theelastomeric propylene copolymer (E) are defined more precisely.

The random propylene copolymer (R-PP) comprises monomers copolymerizablewith propylene, for example comonomers such as ethylene and/or C₄ to C₁₂α-olefins, in particular ethylene and/or C₄ to C₈ α-olefins, e.g.1-butene and/or 1-hexene. Preferably the random propylene copolymer(R-PP) according to this invention comprises, especially consists of,monomers copolymerizable with propylene from the group consisting ofethylene, 1-butene and 1-hexene. More specifically the random propylenecopolymer (R-PP) of this invention comprises—apart from propylene—unitsderivable from ethylene and/or 1-butene. In a preferred embodiment therandom propylene copolymer (R-PP) comprises units derivable fromethylene and propylene only.

The comonomer content of the random propylene copolymer (R-PP) is notmore than 7.0 wt.-%, more preferably not more than 6.0 wt.-%, still morepreferably in the range of 1.0 to 7.0 wt.-%, yet more preferably in therange of 1.5 to 6.0 wt.-%, still more preferably in the range of 1.5 to5.5 wt.-%, like in the range of 2.0 to below 5.0 wt.-%.

Further it is appreciated that the propylene copolymer fulfillsinequation (III), more preferably inequation (IIIa), yet more preferablyinequation (Mb), still more preferably inequation (IIIc), still yet morepreferably inequation (IIId),

$\begin{matrix}{{\frac{{Co}({total})}{{Co}\left( {R\; P\; P} \right)} \geq 1.3},} & ({III}) \\{{\frac{{Co}({total})}{{Co}\left( {R\; P\; P} \right)} \geq 1.4},} & ({IIIa}) \\{{4.0 \geq \frac{{Co}({total})}{{Co}\left( {R\; P\; P} \right)} \geq 1.3},} & ({IIIb}) \\{{3.5 \geq \frac{{Co}({total})}{{Co}\left( {R\; P\; P} \right)} \geq 1.4},} & ({IIIc}) \\{{3.0 \geq \frac{{Co}({total})}{{Co}\left( {R\; P\; P} \right)} \geq 1.4},} & ({IIId})\end{matrix}$

wherein

-   Co (total) is the comonomer content [wt.-%] of the propylene    copolymer,-   Co (RPP) is the comonomer content [wt.-%] of the random propylene    copolymer (R-PP).

The term “random” indicates that the comonomers of the random propylenecopolymer (R-PP), as well as of the first propylene copolymer fraction(R-PP1) and the second propylene copolymer fraction (R-PP2) are randomlydistributed within the propylene copolymers. The term random isunderstood according to IUPAC (Glossary of basic terms in polymerscience; IUPAC recommendations 1996).

The comonomer content of the matrix (M), i.e. of the random propylenecopolymer (R-PP), has also impact on the amount of xylene cold solublesin the matrix (M). Thus it is preferred that the amount of the xylenecold soluble (XCS) fraction of the matrix (M), i.e. of the randompropylene copolymer (R-PP), is equal or below 20.0 wt.-%, morepreferably is in the range of 8.0 to equal or below 20.0 wt.-%, like inthe range of 10.0 to 18.0 wt.-%.

The random propylene copolymer (R-PP) preferably has a melt flow rateMFR₂ (230° C.) in the range of more than 0.5 to equal or below 3.0 g/10min, like in the range of more than 0.5 to below 3.0 g/10 min, morepreferably in the range of more than 0.5 to 2.5 g/10 min, still morepreferably in the range of 0.6 to 1.7 g/10 min, like in the range of 0.7to below 1.5 g/10 min.

The random propylene copolymer (R-PP) preferably comprises at least twopolymer fractions, like two or three polymer fraction, all of them arepropylene copolymers. Preferably the random propylene copolymer (R-PP)comprises at least two different random propylene copolymer fractions,like two different random propylene copolymer fractions, wherein furtherthe two random propylene copolymer fractions differ in the comonomercontent and/or in the melt flow rate MFR₂ (230° C.), preferably differin the comonomer content and in the melt flow rate MFR₂ (230° C.).

Preferably one fraction of the two random polymer copolymer fractions ofthe random propylene copolymer (R-PP) is the commoner lean fraction andthe other fraction is the comonomer rich fraction, wherein further thelean fraction and the rich fraction fulfils inequation (IV), morepreferably inequation (IVa), still more preferably inequation (IVb),

$\begin{matrix}{{\frac{{Co}\mspace{14mu} ({lean})}{{Co}\mspace{14mu} ({rich})} \leq 055},} & ({IV}) \\{{0.10 \leq \frac{{Co}\mspace{14mu} ({lean})}{{Co}\mspace{14mu} ({rich})} \leq 0.50},} & ({IVa}) \\{0.15 \leq \frac{{Co}\mspace{14mu} ({lean})}{{Co}\mspace{14mu} ({rich})} \leq 0.45} & ({IVb})\end{matrix}$

wherein

-   Co (lean) is the comonomer content [wt.-%] of the random propylene    copolymer fraction with the lower comonomer content,-   Co (rich) is the comonomer content [wt.-%] of the random propylene    copolymer fraction with the higher comonomer content.

In addition or alternatively to inequation (IV) one fraction of the tworandom polymer copolymer fractions of the random propylene copolymer(R-PP is the low melt flow rate MFR₂ (230° C.) fraction and the otherfraction is the high melt flow rate MFR₂ (230° C.) fraction, whereinfurther the low flow fraction and the high flow fraction fulfilsinequation (V), more preferably inequation (Va), still more preferablyinequation (Vb),

$\begin{matrix}{\frac{{MRF}\mspace{14mu} ({high})}{{MFR}\mspace{14mu} ({low})} \geq 1.80} & (V) \\{15.0 \geq \frac{{MFR}\mspace{14mu} ({high})}{{MFR}\mspace{14mu} ({low})} \geq 2.50} & ({Va}) \\{12.0 \geq \frac{{MFR}\mspace{14mu} ({high})}{{MFR}\mspace{14mu} ({low})} \geq 4.50} & ({Vb})\end{matrix}$

wherein

-   MFR (high) is the melt flow rate MFR₂ (230° C.) [g/10 min] of the    random propylene copolymer fraction with the higher melt flow rate    MFR₂ (230° C.),-   MFR (low) is the melt flow rate MFR₂ (230° C.) [g/10 min] of the    random propylene copolymer fraction with the lower melt flow rate    MFR₂ (230° C.).

Even more preferred the random propylene copolymer (R-PP) comprises,preferably consists of, a first propylene copolymer fraction (R-PP1) anda second propylene copolymer fraction (R-PP2), wherein further the firstpropylene copolymer fraction (R-PP1) and the second propylene copolymerfraction (R-PP2) differ in the comonomer content and/or in the melt flowrate MFR₂ (230° C.), preferably differ in the comonomer content and inthe melt flow rate MFR₂ (230° C.).

Thus in one embodiment the first random propylene copolymer fraction(R-PP1) has a higher comonomer content and melt flow rate MFR₂ (230° C.)than the second random propylene copolymer fraction (R-PP2).

In another embodiment the second random propylene copolymer fraction(R-PP2) has a higher comonomer content and melt flow rate MFR₂ (230° C.)than the first random propylene copolymer fraction (R-PP1).

In still another embodiment the first random propylene copolymerfraction (R-PP1) has a higher comonomer content but a lower melt flowrate MFR₂ (230° C.) than the second random propylene copolymer fraction(R-PP2);

In further embodiment the second random propylene copolymer fraction(R-PP2) has a higher comonomer content but a lower melt flow rate MFR₂(230° C.) than the first random propylene copolymer fraction (R-PP1).

Thus it is especially preferred that the first random propylenecopolymer fraction (R-PP1) and the second random propylene copolymerfraction (R-PP2) fulfill together the inequation (VI), more preferablyinequation (VIa), still more preferably inequation (VIb),

$\begin{matrix}{{\frac{{Co}\mspace{14mu} \left( {R - {{PP}\; 1}} \right)}{{Co}\mspace{14mu} \left( {R - {{PP}\; 2}} \right)} \leq 0.55},} & ({VI}) \\{{0.10 \leq \frac{{Co}\mspace{14mu} \left( {R - {{PP}\; 1}} \right)}{{Co}\mspace{14mu} \left( {R - {{PP}\; 2}} \right)} \leq 0.50},} & ({VIa}) \\{0.15 \leq \frac{{Co}\mspace{14mu} \left( {R - {{PP}\; 1}} \right)}{{Co}\mspace{14mu} \left( {R - {{PP}\; 2}} \right)} \leq 0.45} & ({VIb})\end{matrix}$

wherein

-   Co (R-PP1) is the comonomer content [wt.-%] of the first random    propylene copolymer fraction (R-PP1),-   Co (R-PP2) is the comonomer content [wt.-%] of the second random    propylene copolymer fraction (R-PP2).

In addition or alternatively to inequation (VI) the first randompropylene copolymer fraction (R-PP1) and the second random propylenecopolymer fraction (R-PP2) fulfill together the inequation (VII), morepreferably inequation (VIIa), still more preferably inequation (VIIb),

$\begin{matrix}{\frac{{MFR}\mspace{14mu} \left( {R - {{PP}\; 1}} \right)}{{MFR}\mspace{14mu} \left( {R - {{PP}\; 2}} \right)} \geq 1.80} & ({VII}) \\{15.0 \geq \frac{{MFR}\mspace{14mu} \left( {R - {{PP}\; 1}} \right)}{{MFR}\mspace{14mu} \left( {R - {{PP}\; 2}} \right)} \geq 2.50} & ({VIIa}) \\{12.0 \geq \frac{{MFR}\mspace{14mu} \left( {R - {{PP}\; 1}} \right)}{{MFR}\mspace{14mu} \left( {R - {{PP}\; 2}} \right)} \geq 4.50} & ({VIIb})\end{matrix}$

wherein

-   MFR (R-PP1) is the melt flow rate MFR₂ (230° C.) [g/10 min] of the    first random propylene copolymer fraction (R-PP1),-   MFR (R-PP2) is the melt flow rate MFR₂ (230° C.) [g/10 min] of the    second random propylene copolymer fraction (R-PP2).

In one specific embodiment the random propylene copolymer (R-PP)comprises, preferably consists of, the first random propylene copolymerfraction (R-PP1) and the second random propylene copolymer fraction(R-PP2), wherein further the random propylene copolymer (R-PP) fulfills

(a) the inequation (VIII), more preferably inequation (Villa), stillmore preferably inequation (VIIIb),

$\begin{matrix}{{\frac{{Co}\mspace{14mu} \left( {R - {{PP}\; 1}} \right)}{{Co}\mspace{14mu} \left( {R - {PP}} \right)} \leq 0.65},} & ({VIII}) \\{{0.15 \leq \frac{{Co}\mspace{14mu} \left( {R - {{PP}\; 1}} \right)}{{Co}\mspace{14mu} \left( {R - {PP}} \right)} \leq 0.60},} & ({VIIIa}) \\{0.20 \leq \frac{{Co}\mspace{14mu} \left( {R - {{PP}\; 1}} \right)}{{Co}\mspace{14mu} \left( {R - {PP}} \right)} \leq 0.55} & ({VIIIb})\end{matrix}$

wherein

-   Co (R-PP1) is the comonomer content [wt.-%] of the first random    propylene copolymer fraction (R-PP1),-   Co (R-PP) is the comonomer content [wt.-%] of the random propylene    copolymer fraction (R-PP).    and/or    (b) the inequation (IX), more preferably inequation (IXa), still    more preferably inequation (IXb),

$\begin{matrix}{\frac{{MFR}\mspace{14mu} \left( {R - {{PP}\; 1}} \right)}{{MFR}\mspace{14mu} \left( {R - {PP}} \right)} \geq 0.50} & ({VII}) \\{10.0 \geq \frac{{MFR}\mspace{14mu} \left( {R - {{PP}\; 1}} \right)}{{MFR}\mspace{14mu} \left( {R - {PP}} \right)} \geq 1.00} & ({VIIa}) \\{8.0 \geq \frac{{MFR}\mspace{14mu} \left( {R - {{PP}\; 1}} \right)}{{MFR}\mspace{14mu} \left( {R - {PP}} \right)} \geq 1.50} & ({VIIb})\end{matrix}$

wherein

-   MFR (R-PP1) is the melt flow rate MFR₂ (230° C.) [g/10 min] of the    first random propylene copolymer fraction (R-PP1),-   MFR (R-PP) is the melt flow rate MFR₂ (230° C.) [g/10 min] of the    random propylene copolymer fraction (R-PP).

Thus it is preferred that the first random propylene copolymer fraction(R-PP1) has a comonomer content of equal or below 4.0 wt.-%, morepreferably of equal or below 3.5 wt.-%, yet more preferably in the range0.2 to 4.0 wt.-%, still more preferably in the range 0.5 to 3.5 wt.-%,like in the range of 1.0 to 3.0 wt.-%.

As the comonomer of the first random propylene copolymer fraction(R-PP1) preferably is rather low, also its xylene cold soluble (XCS) iscomparably low. Thus it is preferred that the amount of the xylene coldsoluble (XCS) fraction of the first random propylene copolymer fraction(R-PP1) is equal or below than 10.0 wt.-%, more preferably is in therange of 1.0 to 10.0 wt.-%, still more preferably is in the range of 2.0to 9.0 wt.-%, yet more preferably is in the range of 2.5 to 8.0 wt.-%.

Preferably the first random propylene copolymer fraction (R-PP1)preferably has a melt flow rate MFR₂ (230° C.) in the range of in therange of 0.3 to 5.5 g/10 min, more preferably in the range 1.0 to 4.5g/10 min.

On the other hand the second random propylene copolymer fraction (R-PP2)preferably has a comonomer content in the range of 1.0 to 12.0 wt.-%,still more preferably in the range 1.5 to 10.0 wt.-%, yet morepreferably in the range 2.5 to 9.0 wt.-%.

The comonomers of the first random propylene copolymer fraction (R-PP1)and second random propylene copolymer fraction (R-PP2), respectively,copolymerizable with propylene are ethylene and/or C₄ to C₁₂ α-olefins,in particular ethylene and/or C₄ to C₈ α-olefins, e.g. 1-butene and/or1-hexene. Preferably the first random propylene copolymer fraction(R-PP1) and second random propylene copolymer fraction (R-PP2),respectively, comprise, especially consist of, monomers copolymerizablewith propylene from the group consisting of ethylene, 1-butene and1-hexene. More specifically the first random propylene copolymerfraction (R-PP1) and second random propylene copolymer fraction (R-PP2),respectively, comprise—apart from propylene—units derivable fromethylene and/or 1-butene. In a preferred embodiment the first randompropylene copolymer fraction (R-PP1) and the second random propylenecopolymer fraction (R-PP2) comprise the same comonomers, i.e. ethyleneonly.

Preferably the second random propylene copolymer fraction (R-PP2)preferably has a melt flow rate MFR₂ (230° C.) in the range of in therange of 0.1 to 5.5 g/10 min, more preferably in the range 0.3 to 4.5g/10 min.

Preferably the weight ratio between the first random propylene copolymerfraction (R-PP1) and the second random propylene copolymer fraction(R-PP2) is 20/80 to 80/20, more preferably 30/70 to 70/30, like 40/60 to60/40.

As mentioned above a further component of the heterophasic propylenecopolymer (RAHECO) is the elastomeric propylene copolymer (E) dispersedin the matrix (M), i.e. in the random propylene copolymer (R-PP).Concerning the comonomers used in the elastomeric propylene copolymer(E) it is referred to the information provided for the heterophasicpropylene copolymer (RAHECO) and the random propylene copolymer (R-PP),respectively. Accordingly the elastomeric propylene copolymer (E)comprises monomers copolymerizable with propylene, for examplecomonomers such as ethylene and/or C₄ to C₁₂ α-olefins, in particularethylene and/or C₄ to C₈ α-olefins, e.g. 1-butene and/or 1-hexene.Preferably the elastomeric propylene copolymer (E) comprises, especiallyconsists of, monomers copolymerizable with propylene from the groupconsisting of ethylene, 1-butene and 1-hexene. More specifically theelastomeric propylene copolymer (E) comprises—apart from propylene—unitsderivable from ethylene and/or 1-butene. Thus in an especially preferredembodiment the elastomeric propylene copolymer (E) comprises unitsderivable from ethylene and propylene only. It is especially preferredthat the random propylene copolymer (R-PP) and the elastomeric propylenecopolymer (E) comprises the same comonomers. Accordingly in one specificembodiment the random propylene copolymer (R-PP) and the elastomericpropylene copolymer (E) comprise propylene and ethylene only.

The comonomer content of the elastomeric propylene copolymer (E)preferably is not more than 25.0 wt.-%, still more preferably in therange of 12.0 to 25.0 wt.-%, yet more preferably in the range of morethan 14.0 to 22.0 wt.-%, even more preferably in the range of more than15.0 to 20.0 wt.-%.

The propylene copolymer, i.e. the heterophasic propylene copolymer(RAHECO), as defined in the instant invention may contain up to 5.0wt.-% additives, like α-nucleating agents and antioxidants, as well asslip agents and antiblocking agents. Preferably the additive content isbelow 3.0 wt.-%, like below 1.0 wt.-%

Preferably the propylene copolymer, i.e. the heterophasic propylenecopolymer (RAHECO), comprises an α-nucleating agent. Even more preferredthe present invention is free of β-nucleating agents. Accordingly, theα-nucleating agent is preferably selected from the group consisting of

-   (i) salts of monocarboxylic acids and polycarboxylic acids, e.g.    sodium benzoate or aluminum tert-butylbenzoate, and-   (ii) dibenzylidenesorbitol (e.g. 1,3:2,4 dibenzylidenesorbitol) and    C₁-C₈-alkyl-substituted dibenzylidenesorbitol derivatives, such as    methyldibenzylidenesorbitol, ethyldibenzylidenesorbitol or    dimethyldibenzylidenesorbitol (e.g. 1,3:2,4 di(methylbenzylidene)    sorbitol), or substituted nonitol-derivatives, such as    1,2,3,-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol,    and-   (iii) salts of diesters of phosphoric acid, e.g. sodium    2,2′-methylenebis(4,6,-di-tert-butylphenyl)phosphate or    aluminium-hydroxy-bis[2,2′-methylene-bis(4,6-di-t-butylphenyl)phosphate],    and-   (iv) vinylcycloalkane polymer and vinylalkane polymer (as discussed    in more detail below), and-   (v) mixtures thereof.

Such additives are generally commercially available and are described,for example, in “Plastic Additives Handbook”, 5th edition, 2001 of HansZweifel.

Preferably the propylene copolymer, i.e. the heterophasic propylenecopolymer (RAHECO), contains up to 5 wt.-% of the α-nucleating agent. Ina preferred embodiment, the propylene copolymer, i.e. the heterophasicpropylene copolymer (RAHECO), contains not more than 200 ppm, morepreferably of 1 to 200 ppm, more preferably of 5 to 100 ppm of aα-nucleating agent, in particular selected from the group consisting ofdibenzylidenesorbitol (e.g. 1,3:2,4 dibenzylidene sorbitol),dibenzylidenesorbitol derivative, preferablydimethyldibenzylidenesorbitol (e.g. 1,3:2,4 di(methylbenzylidene)sorbitol), or substituted nonitol-derivatives, such as1,2,3,-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol,vinylcycloalkane polymer, vinylalkane polymer, and mixtures thereof.

It is especially preferred the propylene copolymer, i.e. theheterophasic propylene copolymer (RAHECO), contains a vinylcycloalkane,like vinylcyclohexane (VCH), polymer and/or vinylalkane polymer. In onespecific embodiment the propylene copolymer, i.e. the heterophasicpropylene copolymer (RAHECO), contains a vinylcycloalkane, likevinylcyclohexane (VCH), polymer and/or vinylalkane polymer. Preferablythe vinylcycloalkane is vinylcyclohexane (VCH) polymer is introducedinto the propylene copolymer, i.e. the heterophasic propylene copolymer(RAHECO), by the BNT technology.

The present invention is not only directed to the instant propylenecopolymer, i.e. the heterophasic propylene copolymer (RAHECO), but alsoto molded articles, preferably blow molded article (extrusion blowmolded, injection blow molded or injection stretch blow molded), likeextrusion blow molded article, e.g. bottles, like extrusion blow moldedbottles, made therefrom. Accordingly in a further embodiment the presentinvention is directed to a molded articles, like a molded bottle,preferably to a blow molded article, more preferably to extrusion blowmolded article, like extrusion blow molded bottle, comprising at least70 wt.-%, preferably comprising at least 80 wt.-%, more preferablycomprising at least 90 wt.-%, still more preferably comprising at least95 wt.-%, yet more preferably comprising at least 99 wt.-%, of theinstant propylene copolymer, i.e. the heterophasic propylene copolymer(RAHECO). In one preferred embodiment the molded articles, like a moldedbottle, preferably the blow molded article, more preferably theextrusion blow molded article, like extrusion blow molded bottle,consists of the propylene copolymer, i.e. consists of the heterophasicpropylene copolymer (RAHECO). In one specific embodiment the blow moldedarticle is a blow molded bottle, like an extrusion blow molded bottle.

The applied processes for the manufacture of moulded articles are withinthe knowledge of the skilled person. Reference is made polypropylenehandbook, Nello Pasquini, 2^(rd) edition, Hanser. For instance, in theextrusion blow molding (EBM) process a polymer melt is first extrudedthrough a tubular die into air forming a polymer tube, subsequentlyblowing up said polymer tube (typically called “parison” in thistechnical field) until the outside of the tube reaches the boundaries ofthe mold. To cover the wall of the mold fully with the blown up polymertube is rather difficult compared to injection molding because the airbetween polymer tube and mold has to be removed totally which is ademanding process step. Further the inside of the polymer tube is not incontact with the mold and therefore there is only little possibility toinfluence the inner surface structure of the tube. As a consequencethereof extrusion blown molded articles, like bottles, normally showinferior optical properties compared to any injection molded articles.For instance, the surface property inside and/or outside of extrusionblown bottles is typically non-uniform (flow lines, melt fracture)leading to lower overall gloss and transparency compared to injectionmolded bottles or injection stretched blown molded articles (ISBM).

Typically the molded articles (bottles), preferably to a blow moldedarticles (bottles), more preferably to extrusion blow molded articles(bottles), have a wall thickness in the range of 0.1 to 1.0 mm.

The instant propylene copolymer, i.e. the heterophasic propylenecopolymer (RAHECO), is preferably obtained by a specific process.Accordingly the instant propylene copolymer, i.e. the heterophasicpropylene copolymer (RAHECO), is preferably obtained by a sequentialpolymerization process comprising the steps of

-   (a) polymerizing in a first reactor (R1)    -   propylene and    -   ethylene and/or a C4 to C12 α-olefin, preferably ethylene,    -   obtaining a first polymer fraction, i.e. a first random        propylene copolymer fraction (R-PP1),-   (b) transferring the first polymer fraction, i.e. the first random    propylene copolymer fraction (R-PP1), into a second reactor (R2),-   (c) polymerizing in said second reactor (R2) in the presence of the    first polymer fraction, i.e. of the first random propylene copolymer    fraction (R-PP1), propylene and    -   ethylene and/or a C4 to C12 α-olefin, preferably ethylene,    -   obtaining a second polymer fraction, i.e. a second random        propylene copolymer fraction (R-PP2), the first and second        polymer fraction form the random propylene copolymer (R-PP),-   (d) transferring said random propylene copolymer (R-PP), into a    third reactor (R3),-   (e) polymerizing in said third reactor (R3) in the presence of the    random propylene copolymer (R-PP),    -   propylene and    -   ethylene and/or a C4 to C12 α-olefin, preferably ethylene,    -   obtaining a third polymer fraction, said third polymer fraction        is the elastomeric propylene copolymer (E); the third polymer        fraction and the random propylene copolymer (R-PP), form the        propylene copolymer, i.e. the heterophasic propylene copolymer        (RAHECO), and-   (f) removing the propylene copolymer from the third reactor (R3).

Preferably between the second reactor (R2), and the third reactor (R3)the monomers are flashed out.

The term “sequential polymerization process” indicates that thepropylene copolymer, i.e. the heterophasic propylene copolymer (RAHECO),is produced in at least four reactors, preferably in four reactors,connected in series. Accordingly the present process comprises at leasta first reactor (R1), a second reactor (R2), and a third reactor (R3).The term “polymerization reactor” shall indicate that the mainpolymerization takes place. Thus in case the process consists of threepolymerization reactors, this definition does not exclude the optionthat the overall process comprises for instance a pre-polymerizationstep in a pre-polymerization reactor. The term “consist of” is only aclosing formulation in view of the main polymerization reactors.

As stated above in the first two reactors the matrix (M), i.e. therandom propylene copolymer (R-PP) is produced. More precisely, in thefirst reactor (R1) the first random propylene copolymer fraction (R-PP1)is produced whereas in the second reactor (R2) the second randompropylene copolymer fraction (R-PP2).

The preferred comonomers used in the first reactor (R1) are the same asindicated above, for the first random propylene copolymer fraction(R-PP1). Accordingly especially preferred comonomers are ethylene,1-butene and 1-hexene. In one specific embodiment the comonomer isethylene.

Preferably the weight ratio between the first random propylene copolymerfraction (R-PP1) and the second random propylene copolymer fraction(R-PP2) is 20/80 to 80/20, more preferably 30/70 to 70/30, yet morepreferably 40/60 to 60/40.

Accordingly in the first reactor (R1) a first random propylene copolymerfraction (R-PP1) is produced whereas in the second rector (R2) thesecond random propylene copolymer fraction (R-PP2) is produced obtainingthereby the random propylene copolymer (R-PP). Concerning the individualproperties reference is made to the information provided above.

The comonomers of the random propylene copolymer (R-PP), of the firstrandom propylene copolymer fraction (R-PP1), and of the second randompropylene copolymer fraction (R-PP2) copolymerizable with propylene areethylene and/or C₄ to C₁₂ α-olefins, in particular ethylene and/or C₄ toC₈ α-olefins, e.g. 1-butene and/or 1-hexene. Preferably the randompropylene copolymer (R-PP), the first random propylene copolymerfraction (R-PP1), and the second random propylene copolymer fraction(R-PP2) comprise, especially consist of, monomers copolymerizable withpropylene from the group consisting of ethylene, 1-butene and 1-hexene.More specifically the random propylene copolymer (R-PP), the firstrandom propylene copolymer fraction (R-PP1) and the second randompropylene copolymer fraction (R-PP2) comprise—apart from propylene—unitsderivable from ethylene and/or 1-butene. In a preferred embodiment therandom propylene copolymer (R-PP), the first random propylene copolymerfraction (R-PP1) and the second random propylene copolymer fraction(R-PP2) comprise the same comonomers, i.e. ethylene only.

Further the first random propylene copolymer fraction (R-PP1), i.e. thepolymer of the first reactor (R1), has preferably a xylene cold soluble(XCS) fraction of equal or below than 10.0 wt.-%, more preferably in therange of 1.0 to 10.0 wt.-%, still more preferably in the range of 2.0 to9.0 wt.-%, yet more preferably in the range of 2.5 to 8.0 wt.-%.

On the other hand the second random propylene copolymer fraction(R-PP2), i.e. the polymer produced in the second reactor (R2),preferably has a xylene cold soluble (XCS) fraction of equal or lessthan 40 wt.-%, more preferably in the range of 2 to 35 wt.-%, still morepreferably in the range of 3 to 30 wt.-%.

Accordingly the overall xylene cold soluble (XCS) content in the secondreactor, i.e. the xylene cold soluble (XCS) fraction of the randompropylene copolymer (R-PP), preferably equal or below than 20.0 wt.-%,more preferably is in the range of 8.0 to equal or below 20.0 wt.-%,still more preferably is in the range of 10.0 to 18.0 wt.-%.

After the second reactor (R2) the matrix (M), i.e. the random propylenecopolymer (R-PP), of the propylene copolymer, i.e. the heterophasicpropylene copolymer (RAHECO), is obtained. This matrix (M) issubsequently transferred into the third reactor (R3) in which theelastomeric propylene copolymer (E) is produced (step (e)) and thus thepropylene copolymer, i.e. the heterophasic propylene copolymer (RAHECO),of the instant invention is obtained.

Concerning the individual properties of the elastomeric propylenecopolymer (E) and the propylene copolymer, i.e. the heterophasicpropylene copolymer (RAHECO), reference is made to the informationprovided above.

Preferably the weight ratio between the matrix (M), i.e. the randompropylene copolymer (R-PP), after step (c) and the elastomeric propylenecopolymer (E) produced in the step (e) is 60/40 to 90/10, morepreferably 70/30 to 85/15.

The first reactor (R1) is preferably a slurry reactor (SR) and can beany continuous or simple stirred batch tank reactor or loop reactoroperating in bulk or slurry. Bulk means a polymerization in a reactionmedium that comprises of at least 60% (w/w) monomer.

According to the present invention the slurry reactor (SR) is preferablya (bulk) loop reactor (LR).

The second reactor (R2), and the third reactor (R3) are preferably gasphase reactors (GPR). Such gas phase reactors (GPR) can be anymechanically mixed or fluid bed reactors. Preferably the gas phasereactors (GPR) comprise a mechanically agitated fluid bed reactor withgas velocities of at least 0.2 m/sec. Thus it is appreciated that thegas phase reactor is a fluidized bed type reactor preferably with amechanical stirrer.

Thus in a preferred embodiment the first reactor (R1) is a slurryreactor (SR), like loop reactor (LR), whereas the second reactor (R2),and third reactor (R3) are gas phase reactors (GPR). Accordingly for theinstant process at least three, preferably three polymerizationreactors, namely a slurry reactor (SR), like loop reactor (LR), a firstgas phase reactor (GPR-1), and a second gas phase reactor (GPR-2)connected in series are used. If needed prior to the slurry reactor (SR)a pre-polymerization reactor is placed.

A preferred multistage process is a “loop-gas phase”-process, such asdeveloped by Borealis A/S, Denmark (known as BORSTAR® technology)described e.g. in patent literature, such as in EP 0 887 379, WO92/12182 WO 2004/000899, WO 2004/111095, WO 99/24478, WO 99/24479 or inWO 00/68315.

A further suitable slurry-gas phase process is the Spheripol® process ofBasell.

Preferably, in the instant process for producing the propylenecopolymer, i.e. the heterophasic propylene copolymer (RAHECO), asdefined above the conditions for the first reactor (R1), i.e. the slurryreactor (SR), like a loop reactor (LR), of step (a) may be as follows:

-   -   the temperature is within the range of 40° C. to 110° C.,        preferably between 60° C. and 100° C., like 68 to 95° C.,    -   the pressure is within the range of 20 bar to 80 bar, preferably        between 40 bar to 70 bar,    -   hydrogen can be added for controlling the molar mass in a manner        known per se.

Subsequently, the reaction mixture from step (a) is transferred to thesecond reactor (R2), i.e. gas phase reactor (GPR-1), i.e. to step (c),whereby the conditions in step (c) are preferably as follows:

-   -   the temperature is within the range of 50° C. to 130° C.,        preferably between 60° C. and 100° C.,    -   the pressure is within the range of 5 bar to 50 bar, preferably        between 15 bar to 35 bar,    -   hydrogen can be added for controlling the molar mass in a manner        known per se.

The condition in the third reactor (R3), preferably in the second gasphase reactor (GPR-2), is similar to the second reactor (R2).

The residence time can vary in the three reactor zones.

In one embodiment of the process for producing the propylene copolymer,i.e. the heterophasic propylene copolymer (RAHECO), the residence timethe first reactor (R1), i.e. the slurry reactor (SR), like a loopreactor (LR), is in the range 0.2 to 4 hours, e.g. 0.3 to 1.5 hours andthe residence time in the gas phase reactors will generally be 0.2 to6.0 hours, like 0.5 to 4.0 hours.

If desired, the polymerization may be effected in a known manner undersupercritical conditions in the first reactor (R1), i.e. in the slurryreactor (SR), like in the loop reactor (LR), and/or as a condensed modein the gas phase reactors (GPR).

Preferably the process comprises also a prepolymerization with thecatalyst system, as described in detail below, comprising aZiegler-Natta procatalyst, an external donor and optionally acocatalyst.

In a preferred embodiment, the prepolymerization is conducted as bulkslurry polymerization in liquid propylene, i.e. the liquid phase mainlycomprises propylene, with minor amount of other reactants and optionallyinert components dissolved therein.

The prepolymerization reaction is typically conducted at a temperatureof 0 to 50° C., preferably from 10 to 45° C., and more preferably from15 to 40° C.

The pressure in the prepolymerization reactor is not critical but mustbe sufficiently high to maintain the reaction mixture in liquid phase.Thus, the pressure may be from 20 to 100 bar, for example 30 to 70 bar.

The catalyst components are preferably all introduced to theprepolymerization step. However, where the solid catalyst component (i)and the cocatalyst (ii) can be fed separately it is possible that only apart of the cocatalyst is introduced into the prepolymerization stageand the remaining part into subsequent polymerization stages. Also insuch cases it is necessary to introduce so much cocatalyst into theprepolymerization stage that a sufficient polymerization reaction isobtained therein.

It is possible to add other components also to the prepolymerizationstage. Thus, hydrogen may be added into the prepolymerization stage tocontrol the molecular weight of the prepolymer as is known in the art.Further, antistatic additive may be used to prevent the particles fromadhering to each other or to the walls of the reactor.

The precise control of the prepolymerization conditions and reactionparameters is within the skill of the art.

According to the invention the propylene copolymer, i.e. theheterophasic propylene copolymer (RAHECO), is obtained by a sequentialpolymerization process, as described above, in the presence of acatalyst system comprising a Ziegler-Natta catalyst and optionally anexternal donor, preferably a catalyst system comprising threecomponents, namely as component (i) a Ziegler-Natta procatalyst, andoptionally as component (ii) an organometallic cocatalyst and ascomponent (iii) an external donor represented by formula (IIIa) or(Iamb), preferably represented by formula (IIIa).

The process runs especially efficient by using a Ziegler-Natta catalystsystem, preferably by using a Ziegler-Natta catalyst system as definedherein detail below, and a specific comonomer/propylene ratio in thesecond reactor (R2) and/or in the third (R3) and forth reactor (R4),respectively. Accordingly it is preferred that

(a) the comonomer/propylene ratio [Co/C3], like the ethylene/propyleneratio [C2/C3], in the first reactor (R1), i.e. in step (a), is in therange of 1 to 15 mol/kmol, more preferably in the range of 2 to 8mol/kmol, and/or(b) the comonomer/propylene ratio [Co/C3], like the ethylene/propyleneratio [C2/C3], in the second reactor (R2), i.e. in step (c), is in therange of 10 to 65 mol/kmol, more preferably in the range of 20 to 60mol/kmol, and/or(c) the comonomer/propylene ratio [Co/C3], like the ethylene/propyleneratio [C2/C3], in the third reactor (R3), i.e. in step (e), is in therange of above 120 to 200 mol/kmol, more preferably in the range of 130to 180 mol/kmol.

In the following the used catalyst is defined in more detail.

Preferably component (i) is a Ziegler-Natta procatalyst which contains atransesterification product of a lower alcohol and a phthalic ester.

The procatalyst used according to the invention is prepared by

-   -   a) reacting a spray crystallized or emulsion solidified adduct        of MgCl₂ and a C₁-C₂ alcohol with TiCl₄    -   b) reacting the product of stage a) with a dialkylphthalate of        formula (I)

-   -   wherein R^(1′) and R^(2′) are independently at least a C₅ alkyl        under conditions where a transesterification between said C₁ to        C₂ alcohol and said dialkylphthalate of formula (I) takes place        to form the internal donor        c) washing the product of stage b) or        d) optionally reacting the product of step c) with additional        TiCl₄.

The procatalyst is produced as defined for example in the patentapplications WO 87/07620, WO 92/19653, WO 92/19658 and EP 0 491 566. Thecontent of these documents is herein included by reference.

First an adduct of MgCl₂ and a C₁-C₂ alcohol of the formula MgCl₂*nROH,wherein R is methyl or ethyl and n is 1 to 6, is formed. Ethanol ispreferably used as alcohol.

The adduct, which is first melted and then spray crystallized oremulsion solidified, is used as catalyst carrier.

In the next step the spray crystallized or emulsion solidified adduct ofthe formula MgCl₂*nROH, wherein R is methyl or ethyl, preferably ethyl,and n is 1 to 6, is contacting with TiCl₄ to form a titanised carrier,followed by the steps of

-   -   adding to said titanised carrier    -   (i) a dialkylphthalate of formula (I) with R^(1′) and R^(2′)        being independently at least a C₅-alkyl, like at least a        C₈-alkyl,    -   or preferably    -   (ii) a dialkylphthalate of formula (I) with R^(1′) and R^(2′)        being the same and being at least a C₅-alkyl, like at least a        C₈-alkyl,    -   or more preferably    -   (iii) a dialkylphthalate of formula (I) selected from the group        consisting of propylhexylphthalate (PrHP), dioctylphthalate        (DOP), di-iso-decylphthalate (DIDP), and ditridecylphthalate        (DTDP), yet more preferably the dialkylphthalate of formula (I)        is a dioctylphthalate (DOP), like di-iso-octylphthalate or        diethylhexylphthalate, in particular diethylhexylphthalate,    -   to form a first product,    -   subjecting said first product to suitable transesterification        conditions, i.e. to a temperature above 100° C., preferably        between 100 to 150° C., more preferably between 130 to 150° C.,        such that said methanol or ethanol is transesterified with said        ester groups of said dialkylphthalate of formula (I) to form        preferably at least 80 mol-%, more preferably 90 mol-%, most        preferably 95 mol.-%, of a dialkylphthalate of formula (II)

-   -   with R¹ and R² being methyl or ethyl, preferably ethyl, the        dialkylphthalat of formula (II) being the internal donor and    -   recovering said transesterification product as the procatalyst        composition (component (i)).

The adduct of the formula MgCl₂*nROH, wherein R is methyl or ethyl and nis 1 to 6, is in a preferred embodiment melted and then the melt ispreferably injected by a gas into a cooled solvent or a cooled gas,whereby the adduct is crystallized into a morphologically advantageousform, as for example described in WO 87/07620.

This crystallized adduct is preferably used as the catalyst carrier andreacted to the procatalyst useful in the present invention as describedin WO 92/19658 and WO 92/19653.

As the catalyst residue is removed by extracting, an adduct of thetitanised carrier and the internal donor is obtained, in which the groupderiving from the ester alcohol has changed.

In case sufficient titanium remains on the carrier, it will act as anactive element of the procatalyst.

Otherwise the titanization is repeated after the above treatment inorder to ensure a sufficient titanium concentration and thus activity.

Preferably the procatalyst used according to the invention contains 2.5wt.-% of titanium at the most, preferably 2.2% wt.-% at the most andmore preferably 2.0 wt.-% at the most. Its donor content is preferablybetween 4 to 12 wt.-% and more preferably between 6 and 10 wt.-%.

More preferably the procatalyst used according to the invention has beenproduced by using ethanol as the alcohol and dioctylphthalate (DOP) asdialkylphthalate of formula (I), yielding diethyl phthalate (DEP) as theinternal donor compound.

Still more preferably the catalyst used according to the invention isthe catalyst as described in the example section; especially with theuse of dioctylphthalate as dialkylphthalate of formula (I).

For the production of the propylene copolymer, i.e. the heterophasicpropylene copolymer (RAHECO), according to the invention the catalystsystem used preferably comprises in addition to the specialZiegler-Natta procatalyst an organometallic cocatalyst as component(ii).

Accordingly it is preferred to select the cocatalyst from the groupconsisting of trialkylaluminium, like triethylaluminium (TEA), dialkylaluminium chloride and alkyl aluminium sesquichloride.

Component (iii) of the catalysts system used is an external donorrepresented by formula (IIIa) or (Iamb). Formula (IIIa) is defined by

Si(OCH₃)₂R₂ ⁵  (IIIa)

wherein R⁵ represents a branched-alkyl group having 3 to 12 carbonatoms, preferably a branched-alkyl group having 3 to 6 carbon atoms, ora cyclo-alkyl having 4 to 12 carbon atoms, preferably a cyclo-alkylhaving 5 to 8 carbon atoms.

It is in particular preferred that R⁵ is selected from the groupconsisting of iso-propyl, iso-butyl, iso-pentyl, tert.-butyl,tert.-amyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl andcycloheptyl.

Formula (Iamb) is defined by

Si(OCH₂CH₃)₃(NR^(x)R^(Y))  (Iamb)

wherein R^(x) and R^(y) can be the same or different a represent ahydrocarbon group having 1 to 12 carbon atoms.

R^(x) and R^(y) are independently selected from the group consisting oflinear aliphatic hydrocarbon group having 1 to 12 carbon atoms, branchedaliphatic hydrocarbon group having 1 to 12 carbon atoms and cyclicaliphatic hydrocarbon group having 1 to 12 carbon atoms. It is inparticular preferred that R^(x) and R^(y) are independently selectedfrom the group consisting of methyl, ethyl, n-propyl, n-butyl, octyl,decanyl, iso-propyl, iso-butyl, iso-pentyl, tert.-butyl, tert.-amyl,neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl.

More preferably both R^(x) and R^(y) are the same, yet more preferablyboth R^(x) and R^(y) are an ethyl group.

More preferably the external donor of formula (Iamb) isdiethylaminotriethoxysilane.

More preferably the external donor is selected from the group consistingof diethylaminotriethoxysilane [Si(OCH₂CH₃)₃(N(CH₂CH₃)₂)], dicyclopentyldimethoxy silane [Si(OCH₃)₂(cyclo-pentyl)₂], diisopropyl dimethoxysilane [Si(OCH₃)₂(CH(CH₃)₂)₂] and mixtures thereof. Most preferably theexternal donor is dicyclopentyl dimethoxy silane[Si(OCH₃)₂(cyclo-pentyl)₂].

If desired the Ziegler-Natta procatalyst is modified by polymerizing avinyl compound in the presence of the catalyst system, comprising thespecial Ziegler-Natta procatalyst (component (i)), the external donor(component (iii)) and optionally the cocatalyst (component (ii)),wherein the vinyl compound has the formula:

CH₂═CH—CHR³R⁴

wherein R³ and R⁴ together form a 5- or 6-membered saturated,unsaturated or aromatic ring or independently represent an alkyl groupcomprising 1 to 4 carbon atoms. The so modified catalyst is used for thepreparation of the propylene copolymer, i.e. of the heterophasicpropylene copolymer (RAHECO), according to this invention.

The additives as stated above are added to the propylene copolymer, i.e.to the heterophasic propylene copolymer (RAHECO) preferably byextruding. For mixing/extruding, a conventional compounding or blendingapparatus, e.g. a Banbury mixer, a 2-roll rubber mill, Buss-co-kneaderor a twin screw extruder may be used. The polymer materials recoveredfrom the extruder are usually in the form of pellets. These pellets arethen further processed, e.g. by a (blow) mold forming process asdescribed above.

In the following the present invention is further illustrated by meansof examples.

EXAMPLES 1. Measuring Methods

The following definitions of terms and determination methods apply forthe above general description of the invention as well as to the belowexamples unless otherwise defined.

Calculation of comonomer content of the second propylene copolymerfraction (R-PP2):

$\begin{matrix}{\frac{{C({PP})} - {{w\left( {{PP}\; 1} \right)} \times {C\left( {{PP}\; 1} \right)}}}{w\left( {{PP}\; 2} \right)} = {C\left( {{PP}\; 2} \right)}} & (I)\end{matrix}$

wherein

-   w(PP1) is the weight fraction [in wt.-%] of the first random    propylene copolymer fraction (R-PP1),-   w(PP2) is the weight fraction [in wt.-%] of second propylene    copolymer fraction (R-PP2),-   C(PP1) is the comonomer content [in wt.-%] of the first random    propylene copolymer fraction (R-PP1),-   C(PP) is the comonomer content [in wt.-%] of the random propylene    copolymer (R-PP),-   C(PP2) is the calculated comonomer content [in wt.-%] of the second    random propylene copolymer fraction (R-PP2).

Calculation of the xylene cold soluble (XCS) content of the secondpropylene copolymer fraction (R-PP2):

$\begin{matrix}{\frac{{{XS}({PP})} - {{w\left( {{PP}\; 1} \right)} \times {{XS}\left( {{PP}\; 1} \right)}}}{w\left( {{PP}\; 2} \right)} = {{XS}\left( {{PP}\; 2} \right)}} & ({II})\end{matrix}$

wherein

-   w(PP1) is the weight fraction [in wt.-%] of the first random    propylene copolymer fraction (R-PP1),-   w(PP2) is the weight fraction [in wt.-%] of second random propylene    copolymer fraction (R-PP2),-   XS(PP1) is the xylene cold soluble (XCS) content [in wt.-%] of the    first random propylene copolymer fraction (R-PP1),-   XS(PP) is the xylene cold soluble (XCS) content [in wt.-%] of the    random propylene copolymer (R-PP),-   XS(PP2) is the calculated xylene cold soluble (XCS) content [in    wt.-%] of the second random propylene copolymer fraction (R-PP2).

Calculation of melt flow rate MFR₂ (230° C.) of the second propylenecopolymer fraction (R-PP2):

$\begin{matrix}{{{MFR}\left( {{PP}\; 2} \right)} = 10^{\lbrack\frac{{\log {({{MFR}{({PP})}})}} - {{w{({{PP}\; 1})}} \times {\log {({{MFR}{({{PP}\; 1})}})}}}}{w{({{PP}\; 2})}}\rbrack}} & ({III})\end{matrix}$

wherein

-   w(PP1) is the weight fraction [in wt.-%] of the first random    propylene copolymer fraction (R-PP1),-   w(PP2) is the weight fraction [in wt.-%] of second random propylene    copolymer fraction (R-PP2),-   MFR(PP1) is the melt flow rate MFR₂ (230° C.) [in g/10 min] of the    first random propylene copolymer fraction (R-PP1),-   MFR(PP) is the melt flow rate MFR₂ (230° C.) [in g/10 min] of the    random propylene copolymer (R-PP),-   MFR(PP2) is the calculated melt flow rate MFR₂ (230° C.) [in g/10    min] of the second random propylene copolymer fraction (R-PP2).

Calculation of comonomer content of the elastomeric propylene copolymer(E), respectively:

$\begin{matrix}\frac{{C({RAHECO})} - {{w({PP})} \times {C({PP})}}}{w(E)} & ({IV})\end{matrix}$

wherein

-   w(PP) is the weight fraction [in wt.-%] of the random propylene    copolymer (R-PP), i.e. polymer produced in the first and second    reactor (R1+R2),-   w(E) is the weight fraction [in wt.-%] of the elastomeric propylene    copolymer (E), i.e. polymer produced in the third reactor (R3)-   C(PP) is the comonomer content [in wt.-%] of the random propylene    copolymer (R-PP), i.e. comonomer content [in wt.-%] of the polymer    produced in the first and second reactor (R1+R2),-   C(RAHECO) is the comonomer content [in wt.-%] of the propylene    copolymer, i.e. is the comonomer content [in wt.-%] of the polymer    obtained after polymerization in the third reactor (R4),-   C(E) is the calculated comonomer content [in wt.-%] of elastomeric    propylene copolymer (E), i.e. of the polymer produced in the third    reactor (R3).

MFR₂ (230° C.) is measured according to ISO 1133 (230° C., 2.16 kgload).

Comonomer content, especially ethylene content is measured with Fouriertransform infrared spectroscopy (FTIR) calibrated with ¹³C-NMR. Whenmeasuring the ethylene content in polypropylene, a thin film of thesample (thickness about 250 μm) was prepared by hot-pressing. The areaof absorption peaks 720 and 733 cm⁻¹ for propylene-ethylene-copolymerswas measured with Perkin Elmer FTIR 1600 spectrometer.Propylene-1-butene-copolymers were evaluated at 767 cm⁻¹. The method wascalibrated by ethylene content data measured by ¹³C-NMR. See also“IR-Spektroskopie far Anwender”; WILEY-VCH, 1997 and “Validierung in derAnalytik”, WILEY-VCH, 1997

Intrinsic viscosity is measured according to DIN ISO 1628/1, October1999 (in Decalin at 135° C.).

The xylene solubles (XCS, wt.-%): Content of xylene cold solubles (XCS)is determined at 25° C. according ISO 16152; first edition; 2005 Jul. 1

Hexane soluble (C6-solubles, wt.-%): Content of hexane soluble ismeasured according to European Pharmacopoeia 6.0, EP316

10 g of a sample taken from 0.3 mm thick bottles was put into a 300 mlErlenmeyer flask and 100 ml of n-hexane was added. The mixture wasboiled under stirring in a reflux condenser for 4 h. The hot solutionwas cooled down under stirring for 45 min and filtered under vacuum (G4glasfilter) and the filtrate is put into a round shenk (dried in avacuum oven at 90° C. and weighted with 0.0001 g exactly). Then thehexane was evaporated under a nitrogen stream on a rotary evaporator.The round shenk was dried in a vacuum oven at 90° C. over night and wasput into a desiccator for at least 2 hours to cool down. The shenk wasweighted again and the hexane soluble was calculated therefrom.

Number Average Molecular Weight (M_(n)), Weight Average Molecular Weight(M_(w)) and Polydispersity (Mw/Mn)

are determined by Gel Permeation Chromatography (GPC) according to thefollowing method:

The weight average molecular weight Mw and the polydispersity (Mw/Mn),wherein Mn is the number average molecular weight and Mw is the weightaverage molecular weight) is measured by a method based on ISO16014-1:2003 and ISO 16014-4:2003. A Waters Alliance GPCV 2000instrument, equipped with refractive index detector and onlineviscosimeter was used with 3×TSK-gel columns (GMHXL-HT) from TosoHaasand 1,2,4-trichlorobenzene (TCB, stabilized with 200 mg/L 2,6-Di tertbutyl-4-methyl-phenol) as solvent at 145° C. and at a constant flow rateof 1 mL/min. 216.5 μL of sample solution were injected per analysis. Thecolumn set was calibrated using relative calibration with 19 narrow MWDpolystyrene (PS) standards in the range of 0.5 kg/mol to 11 500 kg/moland a set of well characterized broad polypropylene standards. Allsamples were prepared by dissolving 5-10 mg of polymer in 10 mL (at 160°C.) of stabilized TCB (same as mobile phase) and keeping for 3 hourswith continuous shaking prior sampling in into the GPC instrument.

Melting temperature (T_(m)) and heat of fusion (H_(f)), crystallizationtemperature (T_(c)) and heat of crystallization (H_(c)): measured withMettler TA820 differential scanning calorimetry (DSC) on 5 to 10 mgsamples. DSC is run according to ISO 3146/part 3/method C2 in aheat/cool/heat cycle with a scan rate of 10° C./min in the temperaturerange of +23 to +210° C. Crystallization temperature and heat ofcrystallization (H_(c)) are determined from the cooling step, whilemelting temperature and heat of fusion (H_(f)) are determined from thesecond heating step

Flexural Modulus: The flexural modulus was determined in 3-point-bendingat 23° C. according to ISO 178 on 80×10×4 mm³ test bars injectionmoulded in line with EN ISO 1873-2

Description/Dimension of the Bottles

1 l bottles, having an outer diameter of 90 mm, wall thickness: 0.3 mm;overall-height of 204 mm, height of the cylindrical mantle of 185 mm

Steam sterilization was performed in a Systec D series machine (SystecInc., USA). The samples were heated up at a heating rate of 5° C./minstarting from 23° C. After having been kept for 30 min at 121° C., theywere removed immediately from the steam sterilizer and stored at roomtemperature till processed further.

Transparency, Clarity, and Haze Measurement on Bottles

Instrument: Haze-gard plus from BYK-GardnerTesting: according to ASTM D1003 (as for injection molded plates)Method: The measurement is done on the outer wall of the bottles. Thetop and bottom of the bottles are cut off. The resulting round wall isthen split in two, horizontally. Then from this wall six equal samplesof app. 60×60 mm are cut from close to the middle. The specimens areplaced into the instrument with their convex side facing the haze port.Then the transparency, haze and clarity are measured for each of the sixsamples and the haze value is reported as the average of these sixparallels.

Gloss Measurement on Bottles

Instrument: Sceen TRI-MICROGLOSS 20-60-80 from BYK-Gardner 20Testing: ASTM D 2457 (as for injection molded plates)The bottles: It is measured on the wall of the bottles. The top andbottom of the bottles is cut off. This round wall is then split in two,horizontally. Then this wall is cut into six equal 25 samples of app.90×90 mm, just to fit into a special light trap made for testing oninjection molded parts. Then the gloss at 20° is measured on these sixsamples, and the average value is reported as gloss at 20°.

2. Examples

The catalyst used in the polymerization process for examples E1, E2, CE1and CE2 has been produced as follows: First, 0.1 mol of MgCl₂x3 EtOH wassuspended under inert conditions in 250 ml of decane in a reactor atatmospheric pressure. The solution was cooled to the temperature of −15°C. and 300 ml of cold TiCl₄ was added while maintaining the temperatureat said level. Then, the temperature of the slurry was increased slowlyto 20° C. At this temperature, 0.02 mol of dioctylphthalate (DOP) wasadded to the slurry. After the addition of the phthalate, thetemperature was raised to 135° C. during 90 minutes and the slurry wasallowed to stand for 60 minutes. Then, another 300 ml of TiCl₄ was addedand the temperature was kept at 135° C. for 120 minutes. After this, thecatalyst was filtered from the liquid and washed six times with 300 mlheptane at 80° C. Then, the solid catalyst component was filtered anddried. Catalyst and its preparation concept is described in general e.g.in patent publications EP491566, EP591224 and EP586390. As co-catalysttriethyl-aluminium (TEAL) and as donor dicyclo pentyl dimethoxy silane(D-donor) was used The aluminium to donor ratio is indicated in table 1.Before the polymerization, the catalyst was prepolymerized with vinylcyclohexane in an amount to achieve a concentration of 200 ppmpoly(vinyl cyclohexane) (PVCH) in the final polymer. The respectiveprocess is described in EP 1 028 984 and EP 1 183 307. As additives 0.04wt. % synthetic hydrotalcite (DHT-4A supplied by Kisuma Chemicals,Netherlands) and 0.15 wt % Irganox B 215 (1:2-blend of Irganox 1010(Pentaerythrityl-tetrakis(3-(3′,5′-di-tert.butyl-4-hydroxytoluyl)-propionateand tris(2,4-di-t-butylphenyl)phosphate) phosphite) of BASF AG, Germanywere added to the polymers in the same step. For the production of 1liter round bottles like used for testing in the inventive work a“Fischer Müller” Blow Molding Machine was used. The main processingparameters for the production are as follows:

-   -   Temperature profile: 180 to 200° C. applied in extruder, adapter        and head    -   Melt temperature measured: 190 to 200° C.    -   Speed of extruder (revolution per minute; rpm): 13 to 16 rpm    -   Die gap: the die gap was adjusted to get a bottle with a weight        of 40 g with Borealis grade RB307MO (random propylene copolymer        with a density of 902 kg/m³ and a MFR₂ of 1.5 g/10 min)    -   Cycle time: 12 to 16 seconds

TABLE 1 Polymerization conditions CE1 CE2 CE3 E1 E2 TEAL/D [mol/mol] 1515 15 15 15 Loop MFR₂ [g/10 min] 3.0 3.0 3.2 3.4 3.2 C2 content [wt.-%]1.9 2.0 1.9 2.0 2.2 XCS [wt.-%] 4.1 4.1 4.3 3.8 3.9 H₂/C3 [mol/kmol]2.98 2.95 2.99 2.99 3.00 ratio C2/C3 [mol/kmol] 3.93 3.89 3.96 3.96 3.96ratio 1 GPR MFR₂ [g/10 min] 1.2 1.1 1.1 1.1 1.1 C2 content [wt.-%] 4.44.3 4.6 5.1 4.9 XCS [wt.-%] 14.8 14.6 15.8 15.8 16.2 H₂/C3 [mol/kmol]5.6 5.5 5.6 5.2 5.4 ratio C2/C3 [mol/kmol] 52.7 52.7 52.2 51.8 53.1ratio 2 GPR MFR₂ [g/10 min] 1.4 1.7 1.8 1.1 1.6 C2 content [wt.-%] 10.89.6 9.8 9.0 8.9 XCS [wt.-%] 36.8 33.6 32.9 32.8 32.8 Tm [° C.] 151 150150 150 150 H₂/C3 [mol/kmol] 374 700 1014 369 1011 ratio C2/C3[mol/kmol] 300 305 303 152 151 ratio Split Loop [wt.-%] 33.4 34.2 35.234.3 34.5 1GPR [wt.-%] 40.8 43.6 44.8 45.5 45.7 2GPR [wt.-%] 25.8 22.220.0 20.2 19.8

TABLE 2 Properties CE1 CE2 CE3 IE1 IE2 MFR₂ [g/10 min] 1.4 1.7 1.8 1.11.4 C2 [wt.-%] 10.8 9.6 9.8 9.0 8.9 XCS [wt.-%] 36.8 33.6 32.9 32.8 32.8Tm [° C.] 151 150 150 150 150 C2 of XCS [wt.-%] 20.5 20.2 20.1 18.4 17.5IV of XCS [dl/g] 2.3 1.8 1.8 2.5 2.0 Mw/Mn of XCS [—] 5.7 5.3 5.2 6.45.5 C2 of XCI [wt.-%] 5.2 4.2 4.7 4.4 4.7 Mw/Mn of XCI [—] 5.7 6.0 6.05.2 5.3 Flex Modulus [MPa] 460 470 483 516 522 C6-Solubles [wt.-%] 9.99.4 9.5 4.2 5.0

TABLE 3 Properties on bottles IE1 IE2 CE1 CE2 CE3 CE4 Transparency b.s.[%] 91 92 86 87 88 90 Haze a.s. [%] 25 22 33 26 28 24 Clarity b.s. [%]67 71 66 72 72 89 Gloss 20° b.s. [%] 7 10 6 10 10 BAF b.s. [—] 19 34 1126 25 Transparency a.s. [%] 90 91 83 84 85 89 Haze a.s [%] 26 30 37 3030 33 Clarity a.s [%] 66 63 63 71 68 86 Gloss 20° a.s. [%] 8 8 5 10 10BAF a.s [—] 20 16 9 22 22 CE4 is the commercial LDPE Bormed LE6609-PH ofBorealis AG

1. Propylene copolymer having: (a) a melt flow rate MFR₂ (230° C.)measured according to ISO 1133 in the range of more than 0.8 to below2.5 g/10 min, (b) a xylene cold soluble content (XCS) determinedaccording ISO 16152 (25° C.) in the range of 25.0 to 35.0 wt. %, and (c)a comonomer content in the range of more than 4.5 to 10.0 wt. %, whereinfurther; (d) the comonomer content of xylene cold soluble (XCS) fractionof the propylene copolymer is in the range of 12.0 to 22.0 wt. %, and(e) the intrinsic viscosity (IV) determined according to DIN ISO 1628/1(in decalin at 135° C.) of the xylene cold soluble (XCS) fraction of thepropylene copolymer is in the range of more than 1.5 to below 3.0 dl/g.2. Propylene copolymer according to claim 1, wherein the xylene coldinsoluble (XCI) fraction of the propylene copolymer has a polydispersity(Mw/Mn) of more than 4.9 to 10.0.
 3. Propylene copolymer having: (a) amelt flow rate MFR₂ (230° C.) measured according to ISO 1133 in therange of more than 0.8 to below 2.5 g/10 min, (b) a xylene cold solublecontent (XCS) determined according ISO 16152 (25° C.) in the range of25.0 to 35.0 wt. %, and (c) a comonomer content in the range of morethan 4.5 to 10.0 wt. %, wherein further; (d) the comonomer content ofxylene cold soluble (XCS) fraction of the propylene copolymer is in therange of 12.0 to 22.0 wt. %, and (e) the xylene cold insoluble (XCI)fraction of the propylene copolymer has a polydispersity (Mw/Mn) of morethan 4.9 to 10.0.
 4. Propylene copolymer according to claim 3, whereinthe intrinsic viscosity (IV) determined according to DIN ISO 1628/1 (indecalin at 135° C.) of the xylene cold soluble (XCS) fraction of thepropylene copolymer is in the range of more than 1.5 to below 3.0 dl/g.5. Propylene copolymer according to claim 1, wherein the propylenecopolymer: (a) comprises an α-nucleating agent, and/or (b) has a hexanesoluble content of below 5.5 wt. %, and/or (c) has a xylene coldinsoluble (XCI) fraction with a comonomer content in the range of 3.0 to7.0.
 6. Propylene copolymer according to claim 1, wherein the propylenecopolymer fulfills: (a) inequation (I); $\begin{matrix}{\frac{{Co}\mspace{14mu} ({total})}{{Co}\mspace{14mu} ({XCS})} \leq 0.55} & (I)\end{matrix}$ wherein; Co (total) is the comonomer content [wt. %] ofthe propylene copolymer, Co (XCS) is the comonomer content [wt. %] ofthe xylene cold soluble fraction (XCS) of the propylene copolymer;and/or (b) inequation (II); $\begin{matrix}{2.8 \leq \frac{{Co}\mspace{14mu} ({XCS})}{{Co}\mspace{14mu} ({XCI})} \leq 5.5} & ({II})\end{matrix}$ wherein; Co (XCS) is the comonomer content [wt. %] of thexylene cold soluble (XCS) of the propylene copolymer, and Co (XCI) isthe comonomer content [wt. %] of the xylene cold insoluble (XCI) of thepropylene copolymer.
 7. Propylene copolymer according to claim 1,wherein the propylene copolymer has a melting temperature Tm determinedby differential scanning calorimetry (DSC) in the range of 148° C. to159° C.
 8. Propylene copolymer according to claim 1, wherein thepropylene copolymer is a heterophasic propylene copolymer (RAHECO)comprising a matrix (M) and an elastomeric propylene copolymer (E)dispersed in said matrix (M), wherein said matrix (M) is a randompropylene copolymer (R-PP).
 9. Propylene copolymer according to claim 8,wherein the weight ratio between the matrix (M) and the elastomericpropylene copolymer (E) is 60/40 to 90/10.
 10. Propylene copolymeraccording to claim 8, wherein the random propylene copolymer (R-PP) (a)has a comonomer content in the range of 1.0 to 7.0 wt. %, and/or (b)fulfills inequation (III):$\frac{{Co}\mspace{14mu} ({total})}{{Co}\mspace{14mu} ({RPP})} \geq 1.3$wherein; Co (total) is the comonomer content [wt. %] of the propylenecopolymer, Co (RPP) is the comonomer content [wt. %] of the randompropylene copolymer (R-PP), and/or (c) has a xylene cold soluble (XCS)fraction in the range of 8.0 to below 20.0 wt. %.
 11. Propylenecopolymer according to claim 8, wherein the random propylene copolymer(R-PP) comprises at least two different random propylene copolymerfractions, wherein further the two random propylene copolymer fractionsdiffer in the comonomer content and/or in the melt flow rate MFR₂ (230°C.).
 12. Propylene copolymer according to claim 11, wherein: (a) onefraction of the two random polymer copolymer fractions is the commonerlean fraction and the other fraction is the comonomer rich fraction,wherein further the lean fraction and the rich fraction fulfilsinequation (IV):$\frac{{Co}\mspace{14mu} ({lean})}{{Co}\mspace{14mu} ({rich})} \leq 0.55$wherein; Co (lean) is the comonomer content [wt. %] of the randompropylene copolymer fraction with the lower comonomer content, Co (rich)is the comonomer content [wt. %] of the random propylene copolymerfraction with the higher comonomer content; and/or (b) one fraction ofthe two random propylene copolymer fractions is the low melt flow rateMFR₂ (230° C.) fraction and the other fraction is the high melt flowrate MFR₂ (230° C.) fraction, wherein further the low flow fraction andthe high flow fraction fulfils inequation (V)$\frac{{MFR}\mspace{14mu} ({high})}{{MFR}\mspace{14mu} ({low})} \geq 1.00$wherein; MFR (high) is the melt flow rate MFR₂ (230° C.) [g/10 min] ofthe random propylene copolymer fraction with the higher melt flow rateMFR₂ (230° C.), MFR (low) is the melt flow rate MFR₂ (230° C.) [g/10min] of the random propylene copolymer fraction with the lower melt flowrate MFR₂ (230° C.).
 13. Propylene copolymer according to claim 11,wherein the two random polymer copolymer fractions are a first randompropylene copolymer fraction (R-PP1) and a second random propylenecopolymer fraction (R-PP2), wherein further: (a) the first randompropylene copolymer fraction (R-PP1) has a higher comonomer content andmelt flow rate MFR₂ (230° C.) than the second random propylene copolymerfraction (R-PP2); or (b) the second random propylene copolymer fraction(R-PP2) has a higher comonomer content and melt flow rate MFR₂ (230° C.)than the first random propylene copolymer fraction (R-PP1); or (c) thefirst random propylene copolymer fraction (R-PP1) has a higher comonomercontent but a lower melt flow rate MFR₂ (230° C.) than the second randompropylene copolymer fraction (R-PP2); or (d) the second random propylenecopolymer fraction (R-PP2) has a higher comonomer content but a lowermelt flow rate MFR₂ (230° C.) than the first random propylene copolymerfraction (R-PP1).
 14. Propylene copolymer according to claim 13,wherein: (a) the weight ratio between the first random propylenecopolymer fraction (R-PP1) and the second random propylene copolymerfraction (R-PP2) 20/80 to 80/20, and/or (b) the first random propylenecopolymer fraction (R-PP1) has a comonomer content in the range 0.2 to4.0 wt. %, and/or (c) the second random propylene copolymer fraction(R-PP2) has a comomer content in the range 1.0 to 12.0 wt. %. 15.Propylene copolymer according to claim 8, wherein the elastomericpropylene copolymer (E) has a comonomer content in the range of 12.0 tobelow 25.0 wt. %.
 16. Blow molded article comprising a propylenecopolymer according to claim
 1. 17. Blow molded article according toclaim 16, wherein the article is a bottle.